JPH10328558A - Spherical mesoporous body and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spherical mesoporous body exhibiting excellent performance particularly at the time of being used as an adsorption separating material or a molecular sieve and a producing method of a spherical mesoporous body having small aspect ratio, almost spherical shape and uniform size and the producing method. SOLUTION: The spherical mesoporous body is a silica based porous body having <=2 mm diameter, the central fine pore diameter D in a fine pore diameter distribution is 1-10 nm and total fine pore volume of the fine pore having a diameter ranging from (D-2.5) nm to (D+2.5) nm is >=60% of total fine pore volume. In a X-ray diffraction, one or more peaks exist at the position of diffraction angle (2θ) corresponding to >=1 nm d-value. The producing method of the silica based porous body is by mixing an alkoxy silane, water, a surfactant and an acid and allowing to react with each other to prepare a solution, pouring the solution into an organic solvent, in which an alkali is added, to form a spherical silica-surfactant combined body, next taking out the spherical silica/surfactant combined body and after that, removing the surfactant from the spherical silica/surfactant combined body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a chromatographic filler, an adsorptive separation agent,
The present invention relates to a spherical mesoporous material that can be used as an adsorbent for a heat pump, a catalyst carrier, a molecular sieve, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In a porous body, a pore diameter (in the present specification, it means a diameter of a pore) is in a range of 1 to 10 nm, and the pore diameter is distributed in a particularly narrow range. The porous body is called a mesoporous body. Such a mesoporous body, particularly a silica-based one, is excellent in that the structure is stable.

[0003] Conventionally, as a method for producing a silica-based mesoporous material, for example, a method of synthesizing a layered silicate as a silica source as a starting material (JP-A-6-24867)
), A method of synthesizing an alkoxysilane compound as a starting material (JP-A-8-69072) is known.

[0004]

However, the mesoporous silica material obtained by the above-mentioned conventional manufacturing method has an irregular shape, has sharp projections, and has a large aspect ratio.
That is, it was difficult to obtain a porous silica having a substantially spherical shape.

When such a conventional mesoporous silica material is used as an adsorbing and separating material, problems such as pressure loss and filter clogging due to abrasion, and the incorporation of broken materials into the separated material are likely to occur. In addition, the performance as an adsorption separation material was insufficient. Furthermore, such silica-based mesoporous materials are not uniform in shape, and therefore have poor classification efficiency.

As a conventional method for producing spherical silica particles, for example, a method of synthesizing an alkoxysilane compound by hydrolytic polycondensation in an aqueous / alcoholic ammoniacal medium (Japanese Patent Publication No. 8-25739). )
It has been known. However, even in this method, 1-1
It was difficult to obtain a mesoporous material having a uniform pore diameter of about 0 nm.

In view of the above problems, the present invention provides a spherical mesoporous material exhibiting particularly excellent performance when used as an adsorptive separation material or a molecular sieve, a small aspect ratio, a substantially spherical shape, and a uniform size. It is an object of the present invention to provide a method for producing a spherical mesoporous material.

[0008]

According to the first aspect of the present invention, there is provided a silica-based porous body having a plurality of fine pores formed of a sphere having a diameter of 2 mm or less, wherein the central fine pore diameter D of the fine pores is 1 to 10 nm. Spherical mesoporous pores, wherein the total pore volume of pores within the range and having a pore diameter in the range of D-2.5 to D + 2.5 nm is at least 60% of the total pore volume. In the body.

As the above silica-based porous material, besides one made of pure silica, silica (A)
l), titanium (Ti), magnesium (Mg), zirconium (Zr), gallium (Ga), beryllium (Be), yttrium (Y), lanthanum (La), tin (Sn), lead (Pb), vanadium ( V), boron (B) and the like.

The above-mentioned central pore diameter means a pore diameter showing a maximum peak in a pore diameter distribution curve. The pore size distribution curve is a value (dV / d) obtained by differentiating the pore volume (V) of the mesoporous material with the pore size (D).
3 shows a curve in which D) is plotted against the pore diameter (D).

The above pore size distribution curve can be created by the following gas adsorption method. The most frequently used gas in the above gas adsorption method is nitrogen. First, a liquid nitrogen temperature (−196) is applied to the target mesoporous material.
℃), and the adsorption amount is determined by the constant volume method or the gravimetric method. Thereafter, the pressure of the introduced nitrogen gas is gradually increased, and the adsorption isotherm is created by plotting the adsorption amount of the nitrogen gas with respect to each equilibrium pressure. From this adsorption isotherm, for example, Cranston-Inkl
The pore size distribution curve can be derived using the calculation method of the ay method or the Dollimore-Heal method (see Embodiment 3).

Next, in the above claim 1, "D-2.
The total pore volume of pores having a pore diameter in the range of 5 to D + 2.5 nm is 60% or more of the total pore volume. " For example, it is assumed that the mesoporous material α has a center pore diameter of 2.7 nm.
In this mesoporous body α, the pore diameter is 0.2 to 5.2n.
The pore volume V is obtained by summing the pore volumes in the range of m. On the other hand, the total Val of the total pore volume in the mesoporous body α is determined.

If the value of V / Val is assumed to be 0.6
(60%) or more, the mesoporous body α is a spherical mesoporous body according to the present invention. Alternatively, in the pore diameter distribution curve of the mesoporous body α, the pore diameter is 0.2
Even when the integrated value in the range of up to 5.2 nm is 60% or more of the total integrated value of the pore diameter distribution curve, the mesoporous material α
Is a spherical mesoporous material according to the present invention.

In a state where the above conditions are not satisfied,
That is, the case where the value of V / Vall is less than 60% means that the variation of the pore diameter is large. When such a spherical mesoporous material is used as a separating agent, for example,
There is a possibility that sufficient separation performance cannot be obtained. Also, when used as a molecular sieve, there is a possibility that the performance as a sufficient sieve may not be exhibited. In addition, when used as a filler for an adsorption heat pump, there is a possibility that a problem such as not being able to obtain sufficient pumping heat is caused.

The operation of the present invention will be described below. The spherical mesoporous body according to the present invention comprises a sphere having a diameter of 2 mm or less. For this reason, the mechanical strength is high and the packing density can be increased. Therefore, by using the spherical mesoporous material according to the present invention as an adsorption separation material, it is possible to particularly reduce pressure loss and wear. Therefore, mixing of the crushed material into the separated material can be substantially prevented.

If the strength of the adsorptive separation material is low, the adsorptive separation material is crushed during the separation, and the crushed material of the adsorptive separation material is mixed into the separated material, which lowers the purity of the separated material. Was likely to occur. In addition, the crushed material may clog filters and the like provided in the device for performing adsorption separation. By using the spherical mesoporous material according to the present invention, this problem hardly occurs. Further, the spherical mesoporous material according to the present invention has a small aspect ratio, a substantially spherical shape, and a uniform shape, so that it exhibits excellent performance in classification efficiency.

Further, the mesoporous material according to the present invention can separate or adsorb relatively large molecules since the center pore diameter D is in the range of 1 to 10 nm. In addition, the mesoporous material according to the present invention has a uniform pore structure since the total pore volume is 60% or more of the total pore volume, and therefore, can adsorb and separate molecules with high selectivity. It can be carried out. When the mesoporous material of the present invention is used in the adsorption and desorption of water vapor, it can be carried out even with a small difference in vapor pressure.

As described above, according to the present invention, it is possible to provide a spherical mesoporous material exhibiting particularly excellent performance when used as an adsorption separation material or a molecular sieve.

Next, a second aspect of the present invention is a silica-based porous body comprising a sphere having a diameter of 2 mm or less and having a large number of pores, wherein the central pore diameter D of the pores is 1 to 10 nm. A spherical mesoporous material which is within the range and has one or more peaks at a diffraction angle (2θ) corresponding to a d value of 1 nm or more in X-ray diffraction.

The expression "having one or more peaks at a position of a diffraction angle (2θ) corresponding to a d value of 1 nm or more in X-ray diffraction" means that a periodic crystal structure of 1 nm or more is applied to the present invention. It means that it exists in the spherical mesoporous material. That is, the pore diameter of the spherical mesoporous material according to the present invention is 1 nm or more, and the pore diameter has a uniform distribution.

The operation and effect of the present invention will be described below. The spherical mesoporous body according to the present invention comprises a sphere having a diameter of 2 mm or less. Therefore, as in the first aspect, the mechanical strength is high and the packing density can be increased. Therefore, by using the spherical mesoporous material according to the present invention as an adsorption separation material, it is possible to particularly reduce pressure loss and wear. Therefore, mixing of the crushed material into the separated material can be substantially prevented.

The spherical mesoporous material according to the present invention has d
Since there is one or more peaks at the position of the diffraction angle corresponding to the value of 1 nm or more, the aspect ratio is small, the shape is substantially spherical, and the shape is uniform, so that excellent performance is also exhibited in the classification efficiency.

Further, since the mesoporous material according to the present invention has a center pore diameter D in the range of 1 to 10 nm, it is possible to separate or adsorb relatively large molecules as in the first aspect. it can. In addition, the mesoporous material according to the present invention has a uniform pore structure since it has one or more peaks at diffraction angle positions corresponding to d values of 1 nm or more, and therefore has high selectivity for the molecule. Can be adsorbed and separated. When the mesoporous material of the present invention is used in the adsorption and desorption of water vapor, it can be carried out even with a small difference in vapor pressure.

Next, the invention according to claim 3 comprises a sphere,
In producing a spherical mesoporous body having a large number of pores, raw materials of alkoxysilane, water, a surfactant and an acid are mixed and reacted to prepare a solution A, and the solution A is mixed with an organic solvent to which an alkali is added. Injection, producing a spherical silica / surfactant composite, then taking out the spherical silica / surfactant composite, and thereafter removing the surfactant from the spherical silica / surfactant composite. A method for producing a spherical mesoporous body.

As a result, an excellent spherical mesoporous material having uniform pores, high mechanical strength and high packing density can be obtained. According to the present invention, an excellent spherical mesoporous material as described above can be easily produced.

The details of the present invention will be described below. First, the steps involved in preparing the solution A will be described. The method of mixing the raw materials is not particularly limited, but it is preferable to first add water to the alkoxysilane, stir at room temperature for 10 minutes to 3 hours, and then add a surfactant. Also,
The water is preferably added in an amount of 0.5 to 10 mol per 1 mol of silicon contained in the alkoxysilane.

By this mixing method, the alkoxysilane can be slowly condensed via the linear alkoxysilane polymer. Therefore, a dense silica structure is formed, and a high-density spherical mesoporous body can be produced. When the spherical mesoporous material having a high density is used by filling it in a container as an adsorbent, a catalyst, or the like, the container can be filled with a larger amount of the spherical mesoporous material as compared with the related art. Thereby, higher adsorption characteristics, higher catalyst characteristics, and the like can be exhibited. Alternatively, the size of the filling container can be easily reduced.

If the amount of the water is less than 0.5 mol, the hydrolysis of the alkoxysilane becomes insufficient.
There is a possibility that a strong spherical mesoporous skeleton cannot be formed. Alternatively, only a low-density spherical mesoporous body may be obtained. On the other hand, when more than 10 mol of water is added, hydrolysis and condensation of the alkoxysilane are rapidly performed, the silica structure becomes coarse, and the density of the spherical mesoporous body may decrease.

If the stirring time is less than 10 minutes, the density of the spherical mesoporous material may decrease. On the other hand, when the time exceeds 3 hours, uniform pores may not be formed.

Further, at the time of the mixing, an acid as a pH adjuster is added. Thereby, the electrophilic reaction proceeds, and one of the alcohol groups of the alkoxide becomes an OH group. Thereby, a hydrophobic group (alcohol group) and a hydrophilic group (OH group) coexist, and it is easy to react linearly, and mixing can be uniform.

The pH at the time of the mixing is preferably adjusted to a range of 1 to 4. If the pH is less than 1, hydrolysis and condensation proceed rapidly, and the formation of uniform pores may be hindered. Alternatively, the density of the spherical mesoporous body may decrease. On the other hand, if the pH is higher than 4, the components may not be sufficiently dissolved, and the necessary hydrolysis may not be performed. As the acid, dilute hydrochloric acid (for example, 2N) can be used, but another acid such as sulfuric acid may be used.

The above-mentioned surfactant may be added as a powder, or may be added after dissolving in a small amount of water. The surfactant is preferably added in an amount of 0.01 to 10 mol per 1 mol of silicon contained in all the raw materials. When the addition amount of the surfactant is more than 10 mol, the surplus surfactant not involved in the formation of the spherical silica / surfactant complex is mixed in the spherical silica / surfactant complex, There is a possibility that it becomes difficult to obtain a spherical mesoporous material having a high density. In addition, the manufacturing cost may increase.

On the other hand, when the addition amount is less than 0.01 mol, excess silica not involved in the formation of the spherical silica / surfactant complex is mixed in the spherical silica / surfactant complex. However, the ratio of the portion where uniform pores are formed may decrease, and the required function may not be sufficiently exhibited. Further, the excess silica may form a thick layer on the surface of the spherical silica / surfactant composite and adhere thereto. In this case, the pore volume of the spherical mesoporous body decreases.

The alkoxysilane used as the raw material includes tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane, trimethoxysilane, triethoxysilane,
Trimethoxysilanol, triethoxysilanol, methyltrimethoxysilane, trimethoxyvinylsilane,
Triethoxyvinylsilane, 3-glycidoxypropylpropylsilane, 3-mercaptopropyltrimethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- (2-aminoethylaminopropyl) trimethoxysilane Phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydimethylsilane, dimethoxymethylsilane, diethoxy-3-glycidoxypropylmethylsilane, 3
-Chloropropyldimethylmethoxysilane, dimethoxydiphenylsilane, dimethoxydimethylphenylsilane, trimethylmethoxysilane, trimethylethoxysilane, dimethylethoxysilane, dimethoxydiethoxysilane, γ- (methacryloxypropyl) trimethoxysilane, β- (3,4 Alkoxyalkoxysilanes such as -epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropylethoxysilane, N-phenyl-3-aminopropylethoxysilane, and 3-dimethylaminopropyltrimethoxysilane can be used.

Further, a mixture of two or more of the above-described alkylalkoxysilanes can be used. In addition, it is particularly preferable to use tetraalkoxysilane as the alkoxysilane.

In the present invention, alkoxysilane is used as a substance serving as a silica source. However, instead of this, an organic silicon salt compound, an organic acid ester compound of silicon, a silanol group-containing organic compound, or the like may be used. , A silica-based mesoporous material can be produced. In this case, as the organic silicon salt compound, methyltrichlorosilane, vinyltrichlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, methylvinyldichlorosilane, trimethylchlorosilane, methyldiphenylchlorosilane and the like can be used.

As the organic acid ester compound of silicon, there can be used tetraacetoxysilane, methylacetoxysilane, funyltriacetoxysilane, diacetoxydimethylsilane, acetoxytrimethylsilane and the like. Further, as the silanol group-containing organic compound, diphenylsilanediol, phenylsilanetriol, trimethylsilanol, dimethylsilanediol and the like can be used.

The above-mentioned surfactant is preferably a compound having an alkyl group and a hydrophilic group. By using this compound, a molecular aggregate of a surfactant is formed in the reaction solution, and 1 to 1 corresponding to the size of the molecular aggregate are formed.
A spherical mesoporous body having uniform pores of 0 nm can be obtained.

The alkyl group in the surfactant preferably has 2 to 18 carbon atoms. By using a surfactant comprising these alkyl groups, the above-mentioned molecular assembly is efficiently formed. In addition, the surfactant having more than 18 carbon atoms is not commercially available and may increase the cost. When the number of carbon atoms is 1, that is, when the alkyl group is a methyl group, the molecular aggregate is difficult to be formed and the spherical mesoporous having uniform pores having a pore diameter of 1 to 10 nm. The body may not be easily formed.

As the hydrophilic group in the surfactant, for example, -N ⁺ (CH ₃ ) ₃ , = N ⁺ (C
^{_{H 3) 2, ≡N +,}} (CH 3) N + ≡, -NH 2, -N
O, -OH, -COO -, - OSO 3 -, - SO 3 -,
-OPO ₃ -,-(CH ₂ CHO) _n H,-(OCH ₂
CH) _n OH and the like.

Next, as the surfactant, a compound represented by the following chemical formula can be used. In addition, it is preferable to use an alkyltrimethylammonium salt as such a compound. Here _{C n H 2n + 1 N (} CH 3) 3 X, n is 2 to 18 integer, X is, for example, chloride ion, a halide ion such as bromide ion.

By using such a surfactant, a molecular aggregate of the surfactant is efficiently formed in the reaction solution, and 1 to 10 nm corresponding to the size of the molecular aggregate.
A spherical mesoporous body in which uniform pores are formed can be obtained.

Specific examples of the surfactant represented by the above chemical formula include hexadecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, decyltrimethylammonium bromide, octyltrimethylammonium bromide and the like.

Other surfactants other than the compound represented by the above chemical formula include C _m H _{2m + 1} N (CH ₃ ) ₂ (CH
_{2) 5 N (CH 3)} 2 C m H 2m + dipole ammonium salts as represented by _{1, C n H 3n + 1} N (CH 3) 2 (C
A divalent surfactant represented by H ₂ ) ₅ N (CH ₃ ) ₃ , C _n H _{2n + 1} N (CH ₈ ) _m [(CH ₂ ) _p OH]
Ammonium salt having an OH group represented by _3-m , C
_{n H 2n + 1 N (CH} 3) 2 (CH 2) m C 6 H can be used benzalkonium salts, such as expressed by _5.

Further, C _{n + 1} H _{2n + 1} [N (CH ₃ ) ₂ ] _{m
(CH 2) p Si (OCH} 3) an organosilane compound such as represented by _{3, C n H 2n + 1} N + (CH 3) 2 RX - (RX
^- ; Sulfates, acetates, etc.) can also be used as surfactants. The surfactants may be used alone or in combination of two or more.

Next, the step of injecting the solution A into an organic solvent will be described in detail. In this step, the raw material contained in the solution A becomes a silica / surfactant composite, which is spheroidized when gelled. For this reason, this step is called a spheroidization method.

There are various methods for the spheroidization.
Generally, the solution A is injected into an organic solvent in which the solution A is insoluble, a spherical silica / surfactant complex is formed, and then the alkali is added to gel the solution A. Thereafter, the spherical silica / surfactant composite is taken out of the organic solvent.
It is preferable to perform such a method. As a specific example of the spheroidizing method, an oil setting method and an emulsion method described below are preferably performed.

The above alkali can be added to the organic solvent before adding the solution A in advance. Also, it can be added after the spherical silica / surfactant composite is formed. In addition to using an alkali species (powder, gas, liquid, etc.), the alkali may be used by dissolving the alkali species in a suitable solvent in advance to form a solution.

As the alkali, it is preferable to use ammonia or amines soluble in an inorganic amine such as ammonia or an organic solvent such as an organic amine such as trimethylamine or triethylamine.

In the oil setting method, the solution A is ejected in the air through a nozzle to form droplets, and the droplets are dissolved in an organic solvent in which the solution A is insoluble and the alkali is added in advance. This is a method of obtaining the above-mentioned spherical silica / surfactant composite by curing the mixture. When the solution A is ejected in the air via a nozzle, a constant voltage may be applied between the nozzle and an electrode provided separately to form a droplet between the two electrodes.

Further, droplets can be ejected directly to the organic solvent. The size of the spherical silica / surfactant composite produced in the above oil setting method can be controlled by the diameter of the nozzle used and the ejection speed of the solution A. Thereby, a spherical mesoporous body having a desired size can be manufactured.

In the emulsion method, the organic solvent to which the solution A has been added (in the present method, the organic solvent acts as a dispersion medium) is rapidly stirred by a high-speed stirrer. As a result, the solution A is emulsified to generate emulsified sol microdroplets. The microdroplets are added to the alkaline solution to form a spherical silica / surfactant complex in the solution while the solution is gelled.

Examples of the alkaline solution include inorganic amines such as ammonia, and trimethylamine, triethylamine, tri-n-propylamine, tributylamine, tripentylamine, trippropargylamine,
N, N, N-trimethylethylenediamine, tri-1-
It is preferable to use organic amines such as hexylamine and N-dimethylbenzylamine, or ammonia or amines soluble in an organic solvent dissolved in an appropriate solvent.

In addition, in the above-mentioned emulsion method, when adding the solution A to the organic solvent, the above-mentioned surfactant can be added to the organic solvent as a floating agent in advance. In this case, as the surfactant, an anionic surfactant,
It is preferred to use a non-ionic surfactant.

Examples of the anionic surfactant include synthetic fatty acid salts, monoalkyl sulfosuccinates, acyl sarcosine salts, alkyl sulfates, alkyl phosphates, and the like.
Polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, fatty acid monoglyceride sulfate, alkyl sulfonate, alkyl allyl sulfonate, etc. Can be used.

Examples of the nonionic surfactant include fatty acid monoglyceride, sorbitan fatty acid partial ester, sugar fatty acid partial ester, polyglycerin fatty acid partial ester, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether,
Polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyoxyethylene glycerin fatty acid partial ester, polyoxyethylene fatty amide, polyoxyethylene fatty amine, polyoxyethylene (hardened) castor oil, polyethylene glycol fatty acid ester, poly Oxyethylene polyoxypropylene / block polymer can be used.

The organic solvent to which the solution A is added in the present invention is not limited to the oil set method and the emulsion method, and is preferably a solvent that is immiscible with the solution A.
Examples of such an organic solvent include petroleum hydrocarbons such as kerosene and Isobar U (trade name, manufactured by Esso Standard Oil Co.); and non-polar hydrocarbons such as hexane, octane, cyclohexane, cyclopentane, benzene, toluene and xylene. Hydrogen; carbon tetrachloride, trichloroethylene,
Halogenated hydrocarbons such as tetrachloroethylene and dichlorobenzene; ethers such as diethyl ether and isopropyl ether; esters such as ethyl acetate, propyl acetate and phenyl acetate; alcohols such as octyl alcohol and benzoyl alcohol can be used. Among them, the use of hexane is particularly effective. These organic solvents may be used alone,
Two or more types may be used in combination.

Next, the step of removing the surfactant from the spherical silica / surfactant composite will be described. Examples of the method for removing the surfactant from the obtained spherical silica / surfactant composite include a method using calcination and a method using a solvent.

First, a removing method by firing will be described. The spherical silica / surfactant composite is heated in the range of 400 ° C to 1000 ° C, preferably in the range of 500 ° C to 700 ° C. If the heating time is 30 minutes or more, the surfactant can be removed to a degree that does not hinder practical use. However, from the above spherical silica / surfactant composite,
In order to completely remove the surfactant, it is preferable to heat for 1 hour or more.

If the heating temperature is lower than 400 ° C., the temperature may be too low and the surfactant may not be sufficiently removed by burning. On the other hand, when the heating temperature exceeds 1000 ° C., the temperature is too high, and the pore structure may be collapsed. In addition, the atmosphere for the heating may be air-flow. However, since a large amount of combustion gas is generated, it is preferable to flow an inert gas such as nitrogen gas at the beginning of heating.

Next, a removing method using a solvent will be described. The spherical silica / surfactant complex is dispersed in a solvent having high solubility for the surfactant, and the mixture is stirred. afterwards,
The solid content in the solvent is recovered. It is a spherical mesoporous body from which this solid content is to be obtained. As the solvent, for example, alcohols such as ethanol and methanol, and acetone and the like can be used.

Further, a small amount of a cation component may be added to the solvent. Thereby, the surfactant can be rapidly dissolved and dispersed in the solvent. In addition, in order to add the cation component to the solvent,
It is preferable to add hydrochloric acid, acetic acid, sodium chloride, potassium chloride and the like. Thereby, the surfactant can be more efficiently separated from the spherical silica / surfactant composite.

It is preferable that the concentration of the cation added is 10 mol / l or less based on the solvent. If the above concentration is more than 10 mol / l,
There is no effect of adding any more, which may increase the cost. In addition, the silica skeleton of the spherical mesoporous material may collapse.

Next, the dispersion amount of the spherical silica / surfactant complex in the above solvent is preferably 0.5 to 50 g per 100 ml of the solvent. When the dispersion amount is less than 0.5 g, the processing efficiency of the spherical silica / surfactant composite is poor, and the cost of the solvent and the production cost may be increased. On the other hand, if it is more than 50 g, the separation of the surfactant becomes insufficient, and the surfactant may remain in the spherical mesoporous body.

Further, it is preferable that stirring after dispersing the spherical silica / surfactant composite in the above-mentioned solvent is performed in a temperature range of 25 to 100 ° C. Thereby, the processing time for separating the surfactant can be shortened.
If the temperature is lower than 25 ° C., there is a possibility that the processing time is hardly reduced. On the other hand, when the temperature exceeds 100 ° C., the energy cost for heating increases,
The loss due to evaporation of the solvent may increase.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A method for producing a spherical mesoporous body according to an embodiment of the present invention will be described. In this example, a spherical mesoporous body is produced using an oil setting method. The spherical mesoporous body according to the present example is a silica-based porous body composed of a sphere having a diameter of 2 mm or less and having many pores on its surface. The central pore diameter D of the above pores is in the range of 1 to 10 nm, and the total pore volume of pores having a pore diameter in the range of D-2.5 to D + 2.5 nm is the total pore volume. Is 60% or more, and d value is 1 nm in X-ray diffraction.
There is at least one peak at the position of the diffraction angle (2θ) corresponding to the above.

In producing such a spherical mesoporous material, a raw material of alkoxysilane, water, a surfactant and an acid as a pH adjuster are mixed and reacted to prepare a solution A. The spherical silica / surfactant complex is prepared by injecting into the added organic solvent, and then the spherical silica / surfactant complex is taken out by filtration, and then the spherical silica / surfactant complex is dried and calcined. , Remove the surfactant.

Hereinafter, the manufacturing method according to this embodiment will be described in detail. In this example, tetramethoxysilane was used as the alkoxysilane and dodecyltrimethylammonium bromide was used as the surfactant. Hydrochloric acid was used as a pH adjuster.

First, 3.6 g of water and about 0.1 g of 2N hydrochloric acid were added to 15.2 g of tetramethoxysilane (TMOS), which was an alkoxysilane, and the mixture was stirred at room temperature for 1 hour. Dodecyltrimethylammonium bromide (DD) as a surfactant was added to the solution obtained by the addition and stirring.
An additional 7.71 g of TA +) was added and stirred vigorously for 1 hour, causing the solution to become viscous. This solution is solution A.

10 ml of triethylamine was added to 500 ml of n-hexane, and this solution was treated with an inner diameter of 4 ml.
It was placed in a 0 mm, 500 mm long glass column. This is the organic solvent to which the alkali has been added.

50 ml of the above solution A was put into a plastic syringe with a needle attached to the outlet, and pressed into the glass column from above. As a result, the solution A is dispersed in the organic solvent, and this is gelled. From the above,
A spherical silica / surfactant composite was obtained.

Next, after sedimentation in the above solution for 2 hours, solid-liquid separation was performed by suction filtration. The solid obtained by the separation was dried at a temperature of 70 ° C. for 16 hours to obtain a transparent spherical fine powder gel. This is the separated spherical silica / surfactant complex. Thereafter, the spherical silica / surfactant composite was calcined at 550 ° C. for 6 hours in air. Thus, the surfactant was removed from the spherical silica / surfactant composite to obtain a spherical fine powder. This spherical fine powder is the spherical mesoporous material according to the present example. The performance of the spherical fine powder will be described in a third embodiment.

Embodiment 2 This embodiment describes the production of a mesoporous spherical body using an emulsion method. First, 15.2 g of tetramethoxysilane (TMOS) which is an alkoxysilane
Then, 3.6 g of water and about 0.
1 g was added and stirred at room temperature for 1 hour. 7.71 g of dodecyltrimethylammonium bromide (DDTA +) as a surfactant was added to the solution obtained by this addition and stirring.
Was further added. The solution was stirred vigorously for 1 hour, causing the solution to become viscous. This is solution A.

Next, 40 g of Span (Span 80) as a surfactant was added to 2 liters of n-hexane and dissolved by stirring. This is the organic solvent into which solution A is injected. Then, the solution A was dropped into a 5 liter beaker while stirring using a stirrer to obtain an emulsion.

Next, a solution prepared by dissolving 10 ml of triethylamine in 500 ml of n-hexane was added to the above emulsion. Thus, the solution A was solidified.
Then, after immersion for 2 hours with stirring, solid-liquid separation was performed by suction filtration. The solid obtained by this separation was dried at 70 ° C. for 16 hours to obtain a transparent spherical fine powder gel. Further, the fine powder gel was calcined at a temperature of 550 ° C. for 6 hours in the air. Thus, the surfactant was removed from the spherical silica / surfactant composite to obtain a spherical fine powder. This spherical fine powder is a spherical mesoporous body. The performance of the spherical fine powder will be described in a third embodiment.

Embodiment 3 This embodiment is similar to Embodiments 1 and 2 as shown in FIGS.
This is to evaluate the performance of the spherical mesoporous body produced in the above. In addition, the spherical mesoporous body produced in Embodiment 1 was used as Sample 1 (FSM / 12HB), and the spherical mesoporous body produced in Embodiment 2 was used as Sample 2 (FSM / 12HB).
/ 12HSB).

First, the powder X for sample 1 and sample 2 was
The line diffraction pattern was measured. For the above measurement, DDINT-2200 (DIGA) was used as an X-ray diffraction pattern measurement device.
KU) was used. Then, scanning was performed at 2 degrees (2θ) / min using Cu-Kα as a radiation source. The slit width is 0.5 degrees
0.15 mm-0.5 degrees. The above measurement results are shown in FIGS.

In both cases of the measurement results for the sample 1 and the sample 2 (in both FIGS. 1 and 2), the position of the diffraction angle (2θ) corresponding to the d value of 1 nm or more, that is, 2θ in FIG. = 2.6 degrees, and in FIG. 2, one peak was observed at 2θ = 1.8 degrees. From this result, it was found that Sample 1 and Sample 2 had a regular structure with a period of 1 nm or more.

Next, the pore size distribution curves of Sample 1 and Sample 2 were determined from the nitrogen adsorption isotherm. The nitrogen adsorption isotherm was measured as follows. The device is equipped with a pressure sensor (MKS, Baratron 127AA, range 10)
00 mmHg) and control valve (MSK, 24
8A) Two connected ones were used. This apparatus can automatically introduce nitrogen gas into a vacuum line and into a sample tube.

About 40 mg of each of the samples 1 and 2 was placed in a glass sample tube and connected to a vacuum line. Then, the sample tube was evacuated at room temperature for about 2 hours. The ultimate vacuum at this time was 10 ^-4 mmHg.

The sample tube is immersed in liquid nitrogen, and a predetermined pressure of nitrogen gas is introduced into the vacuum line. After the pressure has stabilized, open the control valve on the sample tube. After the pressure has become constant, record the equilibrium pressure. Equilibrium pressure 0-80
The above operation was repeated at arbitrary 16 to 18 points in the range of 0 mmHg.

The time until equilibrium varies depending on the pressure.
The range was 0-60 minutes. By plotting the adsorption amount obtained from the equilibrium pressure and the pressure change, nitrogen adsorption isotherms of Sample 1 and Sample 2 were created. The result is shown in FIG. Note that the relative vapor pressure on the horizontal axis in the figure is a value obtained by dividing the vapor pressure around the adsorbent (in this case, sample 1 and sample 2) by the saturated vapor pressure at the temperature of the adsorbent.

From this nitrogen adsorption isotherm, Cranston
-A pore size distribution curve was created by the Inkley method.
The result is shown in FIG. Further, the pore diameter showing the maximum peak in the pore diameter distribution curve, ie, the central pore diameter D and the total fineness of the pore volume included in the pore range of D-2.5 to D + 2.5 nm, obtained from FIG. Table 1 shows the ratio of the pore volume.
It was shown to.

As can be seen from Table 1, Sample 1 and Sample 2
Means that the total pore volume of pores having a central pore diameter D in the range of 1 to 10 nm and having a pore diameter in the range of D-2.5 to D + 2.5 nm is 60% of the total pore volume. It turns out that it is above.

FIGS. 7 and 8 show optical micrographs of Samples 1 and 2, respectively. As shown in the figure, it was found that Sample 1 and Sample 2 were spherical bodies having a size of about several μm.

As a comparative sample, nitrogen adsorption isotherm and pore diameter distribution curve of silica gel BW300 for chromatography (manufactured by Fuji Silysia Chemical Ltd.) are shown in FIGS. 5 and 6. The central pore diameter of silica gel BW300 is 5.5n
m and the pore size are distributed in the range of 1 to 10 nm.
However, the ratio of the total pore volume to the pore volume included in the range of D-2.5 to D + 2.5 nm was 56%, and did not reach 60%.

From the above measurement results, it was found that the spherical mesoporous material according to the present invention had uniform pores. In addition, when these spherical mesoporous materials were used as an adsorption separating agent for column chromatography, it was confirmed that no crushed material was mixed into the separated material, and that the classification efficiency was excellent.

[0088]

[Table 1]

[0089]

As described above, according to the present invention, a spherical mesoporous material exhibiting particularly excellent performance when used as an adsorptive separation material or a molecular sieve, and having a small aspect ratio, a substantially spherical shape, and a small size. A method for producing a uniform mesoporous spherical body can be provided.

[Brief description of the drawings]

FIG. 1 shows a sample 1 (FSM / 12
The figure which shows the X-ray diffraction pattern of HB).

FIG. 2 shows a sample 2 (FSM / 12
FIG. 2 is a diagram showing an X-ray diffraction pattern of HSB).

FIG. 3 shows a sample 1 (FSM / 12
HB) and a diagram showing nitrogen adsorption isotherms of Sample 2 (FSM / 12HSB).

FIG. 4 shows a sample 1 (FSM / 12
HB) and a diagram showing pore size distribution curves of Sample 2 (FSM / 12HSB).

FIG. 5 is a comparative example of silica gel B according to the third embodiment.
Explanatory drawing which shows the nitrogen adsorption isotherm of W300.

FIG. 6 is a comparative example of silica gel B according to the third embodiment.
Explanatory drawing which shows the pore diameter distribution curve of W300.

7 is a drawing-substitute photograph (magnification: 85) showing the particle structure of Sample 1 according to Embodiment 3. FIG.

FIG. 8 is a drawing-substitute photograph (× 170) showing the particle structure of Sample 2 according to Embodiment 3.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Shinji Inagaki 41-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside of Toyota Central Research Laboratory Co., Ltd. 41, Yokomichi, Toyoda Central Research Laboratory Co., Ltd. (72) Inventor Yabukiya 1846 Kozoji-cho, Kasugai-shi, Aichi Fuji Silysia Chemical Co., Ltd. 1846 chome, Fuji Silysia Chemical Co., Ltd.

Claims (3)

[Claims] 1. A silica-based porous body comprising a sphere having a diameter of 2 mm or less and having a large number of pores, wherein the central pore diameter D of said pores is in the range of 1 to 10 nm and D-
A spherical mesoporous body characterized in that the total pore volume of pores having a pore diameter in the range of 2.5 to D + 2.5 nm is 60% or more of the total pore volume. 2. A silica-based porous body comprising a sphere having a diameter of 2 mm or less and having a large number of pores, wherein the central pore diameter D of said pores is in the range of 1 to 10 nm and X-rays. In diffraction, a diffraction angle (2) corresponding to a d value of 1 nm or more.
A spherical mesoporous body having one or more peaks at the position of θ). 3. A method for producing a spherical mesoporous body having a large number of pores, comprising a sphere, mixing and reacting raw materials such as alkoxysilane, water, a surfactant and an acid.
The above solution A is poured into an organic solvent to which an alkali is added to form a spherical silica / surfactant complex, and then the spherical silica / surfactant complex is taken out. A method for producing a spherical mesoporous body, comprising removing a surfactant from an agent complex.